CN107532693B

CN107532693B - Power transmission device

Info

Publication number: CN107532693B
Application number: CN201680014799.7A
Authority: CN
Inventors: 林先浩
Original assignee: Sejin IGB Co Ltd
Current assignee: Sejin IGB Co Ltd
Priority date: 2015-03-12
Filing date: 2016-02-17
Publication date: 2020-06-26
Anticipated expiration: 2036-02-17
Also published as: WO2016144015A1; CN107532693A; US20180066743A1; US10890240B2; KR101706985B1; EP3270007B1; EP3270007A1; KR20160109548A; JP2018509571A; JP6530821B2; EP3270007A4

Abstract

The invention discloses a power transmission device. According to an embodiment of the present invention, a power transmission device includes: a linear rack capable of causing a gear to perform a linear motion by interacting with the gear; bending the rack so that the gear can perform a curvilinear motion by interacting with the gear; and a linear-to-curved conversion rack connected to the linear rack and the curved rack between the linear rack and the curved rack, and converting the linear motion and the curved motion of the gear.

Description

Power transmission device

Technical Field

The present invention relates to a power transmission device, and more particularly, to a power transmission device that can achieve a continuous connection between a linear tooth form and a curved tooth form, thereby implementing a continuous linear motion and a curved motion of an indexing system (INDEX) applied to a semiconductor apparatus or a flat display apparatus.

Background

The power transmission apparatus may be applied to various industrial machines including a semiconductor device, a flat display device for LCD, PDP, OLED, or the like, to implement a linear motion or a curved motion.

In other words, the power transmission device may perform a linear motion or a curved motion according to the interaction of the rack and the pinion based on the rotational power of the motor.

For example, when the rack is of a linear type, the object to be moved can perform a linear motion by interacting with the gear. When the rack is of the curved type, the object to be moved can perform a curved movement by interacting with the gear.

Accordingly, various industrial machines (e.g., indexing systems) can implement linear or curvilinear motions by appropriately combining racks and gears based on structure and function.

In order to independently perform the linear motion and the curved motion, a linear rack or a curved rack is separately employed and a gear is combined corresponding to the rack.

However, in order to continuously perform the linear motion and the curved motion without interruption, a linear rack and a curved rack are connected to each other for use. Specifically, when the tooth profile curve of the linear rack or the tooth profile curve of the curved rack is a cycloid curve or a trochoid curve, the linear rack and the curved rack are not easily connected due to structural limitations caused by the difference in curvature.

In other words, according to the related art, the continuous connection between the linear tooth form of the linear rack and the curved tooth form of the curved rack is not easily achieved.

Therefore, when the continuous connection between the linear tooth form of the linear rack and the curved tooth form of the curved rack is not easily achieved, there may be a limitation in the application of the power transmission device to equipment, such as continuous linear motion and curved motion of indexing equipment widely used in semiconductor equipment or flat panel equipment. In view of the foregoing, there is a need for structural improvements to power transmission devices that can address the above-mentioned problems.

Disclosure of Invention

[ detailed description of the invention ]

[ problem ] to

The invention provides a power transmission device which can realize continuous connection between a linear tooth form and a bent tooth form so as to enable an indexing system (INDEX) applied to semiconductor equipment or flat display equipment to implement continuous linear motion and curve motion.

[ advantageous effects ]

According to the present invention, a continuous connection between a linear tooth form and a curved tooth form can be achieved, and thus, an indexing system (INDEX) applied to a semiconductor apparatus or a flat display apparatus can be made to perform a continuous linear motion and a curved motion.

[ best mode ] for carrying out the invention

According to the present invention, a power transmission device includes: a linear rack capable of causing a gear to perform a linear motion by interacting with the gear; a curved rack capable of causing the gear to perform a curved motion by interacting with the gear; and a linear-to-curved conversion rack connected to the linear rack and the curved rack between the linear rack and the curved rack, and converting the linear motion and the curved motion of the gear.

The straight-curved line conversion rack may include: a linear part having linear teeth and connected to the linear rack; and a line-curve converting part having line-curve converting teeth, and having one side connected to the line part and the other side connected to the curved rack.

The linear portion and the linear-curve converting portion may be integrally formed.

The linear teeth may be provided in plural on the linear portion.

The number of the straight-line-curve conversion teeth provided in the straight-line-curve conversion part may be one or two.

The tooth shapes of the opposite side surfaces of the straight-curved switching tooth may be asymmetrically formed with respect to the center line.

The curvature of the first tooth profile formed at one side surface of the straight-curved switching tooth may match the curvature of the tooth profile of the tooth formed at the curved rack.

The curvature of the second tooth profile formed at the other side surface of the straight-curved conversion tooth may match the curvature of the tooth profile of the tooth formed at the straight rack.

The tooth-shaped curve of the linear rack, the tooth-shaped curve of the curved rack and the tooth-shaped curve of the linear-curve conversion rack can be cycloid curves or trochoid curves.

Another power transmission device according to the present invention includes: a linear rack capable of causing a gear to perform a linear motion by interacting with the gear; and a curved rack connected to the linear rack and capable of causing the gear to perform a curved motion by interacting with the gear, wherein a linear-curved conversion tooth for converting between the linear motion and the curved motion of the gear is formed at an end portion of the linear rack connected to the curved rack.

One or two line-and-curve switching teeth may be provided as the line-and-curve switching teeth, and the tooth shapes of the opposite side surfaces of the line-and-curve switching teeth may be asymmetrically shaped with respect to the center line.

The curvature of the first tooth profile formed at one side surface of the straight-curved switching tooth may match the curvature of the tooth profile of the tooth formed at the curved rack. The curvature of the second tooth profile formed at the other side surface of the straight-curved conversion tooth may match the curvature of the tooth profile of the tooth formed at the straight rack. The tooth-shaped curve of the linear rack, the tooth-shaped curve of the curved rack and the tooth-shaped curve of the linear-curve conversion rack can be cycloid curves or trochoid curves.

The gear may include a plurality of power transmission pins having an arrangement structure of a circular shape and rotating corresponding to the tooth shape of the linear rack and the tooth shape of the curved rack.

The gear may further include: a pin rotation support portion connected to the power transmission pin and rotatably supporting the power transmission pin; and an outer rotor motor part disposed at an inner side of the pin rotation support part in a radial direction and connected to the pin rotation support part, and generating a rotational power to rotate the pin rotation support part disposed at an outer side of the outer rotor motor part.

The pin rotation support portion may rotatably support the power transmission pin and include rotor connection bodies integrated with the rotor, and a pair of the rotor connection bodies may be respectively disposed at opposite end portions of the power transmission pin and connected to the power transmission pin.

The external rotor motor part may include: a rotor connected to the pin rotation support portion at an inner side of the pin rotation support portion in the radial direction and rotating together with the pin rotation support portion; and a stator fixedly disposed inside the rotor in a radial direction and rotating the rotor by an applied current.

Drawings

Fig. 1 is a plan view of a structure of a power transmission device according to a first embodiment of the invention;

FIG. 2 is an enlarged view of the major components shown in FIG. 1;

FIG. 3 is an enlarged view of the major components shown in FIG. 2 with the gears removed;

FIG. 4 is an exploded view of FIG. 3;

FIG. 5 is an enlarged view of area A of FIG. 3;

fig. 6 is a plan view of the structure of a power transmission device according to a second embodiment of the invention;

fig. 7 is a plan view of the structure of a power transmission device according to a third embodiment of the invention;

fig. 8 is a plan view of the structure of a power transmission device according to a fourth embodiment of the invention;

fig. 9 is a plan view of the structure of a power transmission device according to a fifth embodiment of the invention;

FIG. 10 is a schematic internal structural view of a gear according to a retrofitted embodiment;

fig. 11 is an exploded perspective view of the power transmission pin and the pin rotation support shown in fig. 10;

FIG. 12 is a cross-sectional view taken along line B-B of FIG. 10; and

fig. 13 is an enlarged view of the outer rotor motor portion shown in fig. 12.

Description of the reference numerals

100: gear 101: gear body

102: power transmission pin 110: linear rack

111: tooth 120: curve rack

121: teeth 130: straight line-curve conversion rack

130 a: linear portion 130 b: straight-line curve conversion part

131: linear teeth 132: straight line-curve conversion tooth

132 a: first tooth 132 b: second tooth form

200: gear 210: linear rack

201: power transmission pin

220: the curved rack 230: straight line-curve conversion rack

232: straight-curved switching tooth 240: rotor connector

241: pin insertion support hole 251: pin support bearing

252: oil seal 260: external rotor motor section

261: the rotor 262: stator

263: the fixed shaft member 270: absolute position sensor

275: closing cover 278: heat sink

279: airflow space portion 280: control circuit

281: power supply circuit 282: wireless communication circuit

283: the MCU circuit 284: external rotor motor drive circuit

290: pin rotation support part

310: linear rack 320: curve rack

330: straight-curved line conversion rack 332: straight line-curve conversion tooth

410: linear rack 420: curve rack

430: straight-curved conversion rack 432: straight line-curve conversion tooth

510 a: first linear rack 510 b: second linear rack

520 a: first curved rack 520 b: second curved rack

532 a: straight-curved conversion tooth 532 b: straight line-curve conversion tooth

532 c: straight-curved conversion tooth a: region(s)

B-B: line C/L: center line

Detailed Description

[ embodiments of the invention ]

For a fuller understanding of the invention, its advantages, and the objects obtained by its implementation, reference should be made to the accompanying drawings which illustrate preferred embodiments of the invention.

Hereinafter, the present invention will be described in detail by explaining preferred embodiments of the invention with reference to the accompanying drawings. In the drawings, like reference numerals designate like elements.

Fig. 1 is a plan view of the structure of a power transmission device according to a first embodiment of the present invention. Fig. 2 is an enlarged view of the main part shown in fig. 1. Fig. 3 is an enlarged view of the main part shown in fig. 2. Fig. 4 is an exploded view of fig. 3. Fig. 5 is an enlarged view of the area a shown in fig. 3.

Referring to these drawings, the power transmission apparatus according to the present embodiment can achieve continuous connection between a linear tooth form and a curved tooth form, thereby enabling an indexing system (INDEX) applied to a semiconductor device or a flat display device to perform continuous linear and curvilinear motions. The power transmission device may include: a gear 100; a linear rack 110 enabling the gear 100 to perform a linear motion; a curved rack gear 120 enabling the gear 100 to perform a curved motion; and a linear-to-curved conversion rack 130 converting the linear motion and the curved motion of the gear 100.

First, the gear 100 may perform a linear motion or a curved motion while rotating and moving along the orbit of the linear rack 110, the linear-to-curved conversion rack 130, and the curved rack 120. In other words, the gear 100 can move along the tracks of the linear rack 110, the linear-to-curved conversion rack 130, and the curved rack 120, or move in the opposite direction of the curved rack 120, the linear-to-curved conversion rack 130, and the linear rack 110.

In the present embodiment, as in fig. 1 and 2, the gear 100 is rotated by inscribing the linear rack 110, the linear-to-curved conversion rack 130, and the curved rack 120, and performs a linear motion or a curved motion. The external connection can be realized as will be described later.

The gear 100 may include a gear body 101 having a disk shape, and a plurality of power transmission pins 102 coupled to the gear body 101.

The power transmission pin 102 has a circular arrangement structure in the gear body 101, and rotates corresponding to the tooth shapes of the

teeth

111, 131, 132, and 121 formed on the linear rack 110, the linear-to-curved conversion rack 130, and the curved rack 120.

To rotate the power transfer pin 102, a number of components may be added to the gear 100.

Therefore, various gears (for example, a lubrication hole gear, a gear having a built-in speed reducer, or an outer rotor motor type gear) not illustrated may be used as the gear 100 in addition to the gear 100 illustrated in the drawings. It can be said that the application of any gear is within the scope of the present invention.

Among the various types of gears, an outer rotor motor type gear will be described in the next embodiment and will be omitted here.

Next, the linear rack 110 enables the gear 100 to perform a linear motion by interacting with the gear 100, and the curved rack 120 enables the gear 100 to perform a curved motion by interacting with the gear 100.

In the present embodiment, as illustrated in fig. 1, a straight-curved line conversion rack 130 is connected to each of opposite end portions of a curved line rack 120 having an approximately semicircular shape, and then, a straight line rack 110 is connected to each straight-curved line conversion rack 130.

As described above, in order to continuously perform the linear motion and the curved motion without interruption of the gear 100, the linear rack 110 and the curved rack 120 are connected to each other. For this, the straight-curved line conversion rack 130 is used.

The linear-to-curved conversion rack 130 is connected to the linear rack 110 and the curved rack 120 between the linear rack 110 and the curved rack 120, and converts the linear motion and the curved motion of the gear 100.

When the tooth profile curve of the linear rack 110 and the tooth profile curve of the curved rack 120 are cycloid curves or trochoid curves, it is difficult to simply connect the linear rack 110 and the curved rack 120 to each other due to structural limitations caused by the difference in curvature.

For reference, the trajectory of a cycloid curve is generated by points on the circumference of a wheel rolling on a linear line. In contrast, the trajectory of the cycloid curve is generated by means of fixed points which are not located on the circumference of the base circle but are located inside or outside the circle.

When the

teeth

111 and 121 of the linear and

curved racks

110 and 120 are formed by using the cycloid curve and the trochoid curve, it is difficult for the linear and

curved racks

110 and 120 to be connected to each other due to structural limitations caused by the difference in curvature of the

teeth

111 and 121. Thus, there has heretofore been no example of using cycloid curves and trochoid curves in the above-described manner.

However, in the present embodiment, since the linear rack 110 and the curved rack 120 are connected by using the linear-curved conversion rack 130, even when the tooth profile curve of the linear rack 110 and the tooth profile curve of the curved rack 120 are cycloid curves or trochoid curves, the linear rack 110 and the curved rack 120 can be flexibly and easily connected to each other without interruption as illustrated in fig. 1.

When the linear rack 110 and the curved rack 120 are flexibly connected by the linear-to-curved conversion rack 130 as illustrated in fig. 1, the power transmission apparatus can be applied to continuously move an indexing device (INDEX) widely used in semiconductor devices or flat panel display devices in a linear motion and a curved motion. Therefore, the range of utilization of the power transmission device can be greatly increased.

The straight-curved line conversion rack 130 according to the present embodiment may include: a linear portion 130a having linear teeth 131 connected to the linear rack 110; and a straight-curved line-to-curve converting part 130b having a straight-curved line-to-curve converting tooth 132, and one side of the straight-curved line-to-curve converting part 130b is connected to the straight tooth 131 of the straight line part 130a and the other side is connected to the curved rack gear 120.

In this state, the straight portion 130a and the straight-curve converting portion 130b may be coupled to each other as separate members in terms of tooth shape. However, the straight line portion 130a and the straight line-curve converting portion 130b may be manufactured to be applied integrally in view of action and reaction required at the time of power transmission.

The linear teeth 131 provided on the linear portion 130a have substantially the same tooth shape as the teeth 111 of the linear rack 110. The linear teeth 131 provided on the linear portion 130a may preferably be in a plural form, for example, at least three or four teeth.

The straight-curved line conversion teeth 132 provided in the straight-curved line conversion part 130b may be one or two.

It is contemplated that the straight-curved switching teeth 132 may be three or more. However, in this case, the expensive gear 100 becomes excessively large, which is not practical. Accordingly, one or two straight-curved conversion teeth 132 may be provided on an end portion of the straight-curved conversion rack 130.

Since the straight-curved conversion teeth 132 are connected to the curved rack gear 120, the straight-curved conversion teeth 132 convert the linear motion of the gear 100 into a curved motion or convert the curved motion of the gear 100 into a linear motion.

The first tooth profile 132a and the second tooth profile 132b located at opposite side surfaces of the straight-curved switching tooth 132 are asymmetrically shaped with respect to the center line C/L shown in fig. 5. In other words, the curvatures of the tooth forms 132a and 132b located at the opposite side surfaces of the straight-curved switching tooth 132 are different from each other with respect to the center line C/L.

Since the tooth shapes 132a and 132b are asymmetrically formed at the opposite side surfaces of the straight-curved transfer tooth 132 in the present embodiment, the straight rack 110 and the curved rack 120 can be easily connected to each other as illustrated in fig. 1 even when the tooth shape curve of the straight rack 110 and the tooth shape curve of the curved rack 120 are cycloid curves or trochoid curves.

In addition, when the power transmission pin 102 of the gear 100 rotates and moves along the

teeth

111 and 121 of the linear rack 110 and the curved rack 120, as illustrated in fig. 2, the gear 100 can stably move without being separated from the track.

In this state, the curvature of the first tooth form 132a formed at one side surface of the straight-curved switching tooth 132 may match the curvature of the tooth form of the tooth 121 formed on the curved rack gear 120. The curvature of the second tooth form 132b formed at the other side surface of the straight-curved conversion tooth 132 may match the curvature of the tooth form of the tooth 111 formed on the straight rack 110.

For reference, the curvature of the first tooth form 132a varies according to a designed curvilinear motion form (i.e., a deceleration rate, a tooth contact rate, an amount of potential, etc.), and the curvature of the second tooth form 132b varies according to a designed linear motion form (i.e., a tooth contact rate, an amount of transmission per one rotation, an amount of potential, etc.). Thus, there can be numerous combinations of the curvatures.

As described above, when the linear rack 110 and the curved rack 120 are connected by using the linear-curved conversion rack 130, the gear 100 may be continuously made to perform a linear motion or a curved motion.

According to the present embodiment having the above-described structure and operation, a continuous connection between the linear tooth profile and the curved tooth profile is achieved, thereby enabling an indexing system (INDEX) applied to a semiconductor device or a flat display device to perform a continuous linear motion and a curved motion.

Fig. 6 is a plan view of the structure of a power transmission device according to a second embodiment of the present invention.

Referring to fig. 6, the power transmission apparatus according to the present embodiment employs a straight-curved conversion rack 230 having straight-curved conversion teeth 232 to connect a straight rack 210 with a curved rack 220 having an approximately semicircular shape.

Unlike the above-described embodiment, the gear 100 may be rotated by circumscribing the linear rack 210, the linear-to-curved conversion rack 230, and the curved rack 220, and perform a linear motion or a curved motion. In other words, the gear 100 can continuously perform the linear motion, the curved motion, and the linear motion without interruption.

Therefore, even when the gear 100 circumscribes the rack, the straight-curved line conversion rack 230 having the straight-curved line conversion teeth 232 is employed, and thus, the straight rack 210 and the curved rack 220 can be flexibly connected to each other.

Even when the structure of the present embodiment is adopted, a continuous connection between the linear tooth profile and the curved tooth profile is achieved, so that an indexing system (INDEX) applied to a semiconductor device or a flat display device performs a continuous linear motion and a curved motion.

Fig. 7 is a plan view of the structure of a power transmission device according to a third embodiment of the present invention. Fig. 8 is a plan view of the structure of a power transmission device according to a fourth embodiment of the present invention.

The power transmission devices illustrated in fig. 7 and 8 each have the following structure: the straight-

curved conversion racks

330 and 430 having the straight-

curved conversion teeth

332 and 432, respectively, are connected to end portions of the pair of

curved racks

320 and 420, each having a semicircular shape, and the

straight racks

310 and 410 are connected between the straight-

curved conversion racks

330 and 430, thereby forming a closed loop.

In this state, the pinion 100 can be continuously rotated along the racks 310 to 330 and 410 to 430 by internally (fig. 7) or externally (fig. 8) connecting the racks 310 to 330 and 410 to 430.

In the above-described structure, since the linear rack 310 and the curved rack 320 and the linear rack 410 and the curved rack 420 are connected by the linear-to-

curved conversion racks

330 and 430, the gear 100 can easily perform a motion according to inscription (fig. 7) or outscription (fig. 8).

Fig. 9 is a plan view of the structure of a power transmission device according to a fifth embodiment of the present invention.

Referring to fig. 9, the power transmission device according to the present embodiment has the following structure: the first curved rack 520a and the second curved rack 520b having different curvatures are connected by the first linear rack 510a and the second linear rack 510 b.

In the above structure, the straight-curved switching teeth 532a to 532c may be provided in a single form or in both forms at the end portion of the first straight rack 510a and the end portion of the second straight rack 510 b.

In addition, since the first linear rack 510a is directly connected to the first curved rack 520a, one or two linear-curved switching teeth 532a may be formed at an end portion of the first linear rack 510a connected to the first curved rack 520 a. The structure and characteristics of the straight-curved switching teeth 532a are the same as those in the above-described embodiment.

In contrast, unlike the first linear rack 510a, since the first curved rack 520a and the second curved rack 520b are connected to opposite end portions of the second linear rack 510b, the straight-

curved transfer teeth

532b and 532c are formed at the opposite end portions of the second linear rack 510 b. In this state, since the curvature of the first curved rack 520a and the curvature of the second curved rack 520b are different from each other, the curvatures of the tooth shapes located at the opposite side surfaces of the straight-

curved transfer teeth

532b and 532c formed at the opposite end portions of the second straight rack 510b may also be different from each other.

FIG. 10 is a schematic internal block diagram of a gear according to a retrofitted embodiment. Fig. 11 is an exploded perspective view of the power transmission pin and the pin rotation support portion shown in fig. 10. Fig. 12 is a sectional view taken along line B-B of fig. 10. Fig. 13 is an enlarged view of the outer rotor motor portion shown in fig. 12.

The structure of the gear 200 may be an external rotor motor type illustrated in fig. 10. As described above, various gears (e.g., a lubrication hole gear or a gear with a built-in speed reducer) may be used as the gear 200.

Referring to fig. 10-13, the gear 200 device may include: a plurality of power transmission pins 201 having an arrangement structure of a circular shape; a pin rotation support 290 rotatably supporting the power transmission pin 201; and an outer rotor motor part 260 disposed inside the pin rotation supporting part 290 in a radial direction and generating a rotational power to rotate the pin rotation supporting part 290.

The power transmission pin 201 interacts with a rack (not shown) as described in the above embodiments.

The pin rotation support 290 is a structure connected with the power transmission pins 201 having a circular arrangement structure and rotatably supports the power transmission pins 201.

The pin rotation support 290 may include a rotor connection body 240, a pin support bearing 251, and an oil seal 252.

The rotor connecting body 240 is a structure that rotatably supports the power transmission pin 201 and is integrated with the rotor 261. A pair of rotor connection bodies 240 are respectively disposed at opposite end portions of the power transmission pin 201 and connected to the power transmission pin 201.

In other words, the pair of rotor connecting bodies 240 are spaced apart from each other in parallel by the length of the power transmission pin 201 or less. The pair of rotor connection bodies 240 are connected to opposite end portions of the power transmission pin 201 and rotatably support the power transmission pin 201.

A plurality of pin insertion support holes 241 into which the power transmission pins 201 are inserted and supported are provided at equiangular intervals in the circumferential direction in the rotor connecting body 240.

The pin support bearings 251 are arranged at equiangular intervals in the circumferential direction of the rotor connecting body 240 in the same number as the power transmission pins 201 and support the rotational movement of the power transmission pins 201. The pin support bearing 251 may employ various rolling bearings having superior rigidity, including ball bearings.

The oil seals 252 are provided in one-to-one correspondence with the pin support bearings 251, and seal the pin insertion support holes 241 of the rotor connecting body 240, which insert and support the power transmission pins 201.

In the present embodiment, since a pair of rotor connection bodies 240 are provided, a pin support bearing 251 and an oil seal 252 are applied to each of the pair of rotor connection bodies 240. In other words, the rotor connection body 240, the pin support bearing 251, and the oil seal 252 may form a symmetrical structure with respect to the power transmission pin 201. Therefore, the assembling work can be easily performed.

The outer rotor motor part 260 is disposed inside the pin rotation support part 290 in the radial direction and connected to the pin rotation support part 290, and generates rotational power to rotate the pin rotation support part 290 disposed outside the outer rotor motor part 260.

In other words, in the power transmission device 200 of the present embodiment, although the outer rotor motor part 260 is disposed inside the pin rotation supporting part 290, the outer rotor motor part 260 rotates the pin rotation supporting part 290 and the power transmission pin 201 (i.e., a structure disposed outside the outer rotor motor part 260). In this case, not only a complicated structure in which a separate motor is directly connected is not required, but also the overall height of the device and the external size of the device can be significantly reduced.

The outer rotor motor part 260 is connected to the pin rotation support 290 at an inner side of the pin rotation support 290 in the radial direction, and may include a rotor 261 rotating together with the pin rotation support 290, and a stator 262 fixedly disposed at the inner side of the rotor 261 in the radial direction and rotating the rotor 261 by an applied current.

The rotor 261 is provided as a magnet, and the stator 262 is provided as a coil structure on which an electric wire is wound. Therefore, when a current is applied to the stator 262, a magnetic force is generated according to Fleming's law.

Since the rotor interface 240 is coupled to the rotor 261, when the rotor 261 rotates, the rotor interface 240 rotates together, and thus the power transmission pin 201 may be induced to rotate.

A fixed shaft 263 is provided inside the stator 262. Unlike the rotatable rotor 261, the fixed shaft 263 is fixed without rotation.

Accordingly, the fixed shaft 263 may be provided with a sensor, such as the absolute position sensor 270. In the present embodiment, an absolute position sensor 270 is coupled to an end of the fixed shaft 263 and senses an absolute position of the power transmission pin 201. For example, when the absolute position is misaligned, control such as forcibly stopping the movement of the outer rotor motor portion 260 may be performed.

A closing cover 275 for protecting the outer rotor motor portion 260 is provided around the outer rotor motor portion 260. The closure cover 275 can protect the outer rotor motor portion 260. When the closure cover 275 is open, a path for maintenance and repair of the external rotor motor portion 260 may be created.

Around the power transmission pin 201, a heat radiation fin 278 for radiating heat generated from the external rotator motor portion 260 is provided at the opposite side of the closing cover 275.

The heat sink 278 may have a housing structure in which various control circuits 280 for controlling the gear 200 according to the present embodiment are provided.

The control circuit 280 may include a power circuit 281, a wireless communication circuit 282, an MCU circuit 283, and an external rotor motor portion drive circuit 284.

In the present embodiment, the power supply circuit 281, the wireless communication circuit 282, the MCU circuit 283, and the external rotor motor section drive circuit 284 are exemplified to be included, but some of these circuits may not be included in the present application.

In the heat sink 278, an airflow space portion 279 for airflow is formed between the external rotor motor portion 260 and the control circuit 280. The airflow space portion 279 can prevent the following phenomena from occurring: heat generated from the external rotor motor part 260 is directly transferred to the control circuit 280, and thus the control circuit 280 is damaged.

While the present invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. Therefore, the scope of the present invention is defined not by the detailed description of the present invention but by the appended claims, and all differences within the scope will be construed as being included in the present invention.

[ Industrial Applicability ]

The power transmission device according to the present invention can be used for various machine tools requiring rotational motion or linear motion, industrial machinery, semiconductor manufacturing facilities or flat display manufacturing facilities, and various logistics transfer facilities.

Claims

1. A power transmission device comprising:

a linear rack capable of causing a gear to perform a linear motion by interacting with the gear;

a curved rack capable of causing the gear to perform a curved motion by interacting with the gear; and

a linear-to-curvilinear conversion rack connected to the linear rack and the curvilinear rack between the linear rack and the curvilinear rack, and converting the linear motion and the curvilinear motion of the gear, characterized in that:

the straight-curved line conversion rack includes:

a linear part having linear teeth and connected to the linear rack; and

a linear-curved conversion part having linear-curved conversion teeth, and having one side integrally formed to the linear part and the other side connected to the curved rack;

wherein the linear portion and the linear-curve converting portion are integrally formed;

the linear teeth are arranged on the linear part in a plurality of forms;

one or two of the straight-line-curve conversion teeth provided in the straight-line-curve conversion portion;

the tooth profiles of the opposite side surfaces of the straight-curved switching tooth are asymmetrically shaped with respect to the center line;

a curvature of a first tooth profile formed at one side surface of the straight-curved conversion tooth matches a curvature of a tooth profile of a tooth formed at the curved rack;

the curvature of the second tooth profile formed at the other side surface of the straight-curved conversion tooth matches the curvature of the tooth profile of the tooth formed at the straight rack.

2. The power transmission device of claim 1, wherein the tooth profile of the linear rack, the tooth profile of the curvilinear rack, and the tooth profile of the linear-to-curvilinear conversion rack are cycloid curves or trochoid curves.

3. The power transmission device according to claim 1, wherein the gear includes a plurality of power transmission pins having an arrangement structure of a circular shape and rotating corresponding to the tooth shape of the linear rack and the tooth shape of the curved rack.

4. The power transmission device of claim 3, wherein the gear further comprises:

a pin rotation support portion connected to the power transmission pin and rotatably supporting the power transmission pin; and

an outer rotor motor part disposed at an inner side of the pin rotation support part in a radial direction and connected to the pin rotation support part, and generating a rotational power to rotate the pin rotation support part disposed at an outer side of the outer rotor motor part,

the external rotor motor part includes:

a rotor connected to the pin rotation support portion at an inner side of the pin rotation support portion in the radial direction and rotating together with the pin rotation support portion; and

a stator fixedly disposed inside the rotor in a radial direction and rotating the rotor by an applied current.

5. The power transmission device according to claim 4, wherein the pin rotation support portion rotatably supports the power transmission pin and includes a rotor connection body integrated with the rotor, and

a pair of the rotor connection bodies are respectively disposed at opposite end portions of the power transmission pin and connected to the power transmission pin.